Method of production of semiconductor light emission device and method of production of light emission apparatus

ABSTRACT

A method of production of semiconductor light emission devices for forming stripes of two multilayers having different emission wavelengths on a substrate, including the steps of: depositing a first multilayer including an active layer on the substrate; selectively etching the first multilayer to form a plurality of adjoining pairs of stripes of the first multilayer; depositing a second multilayer including an active layer on the substrate and the stripes of the first multilayer; selectively etching the second multilayer to form a plurality of adjoining pairs of stripes of the second multilayer on the substrate between the stripes of the first multilayer; and dividing the substrate between adjoining pairs of stripes of the first multilayer and between adjoining pairs of stripes of the second multilayer to divide it into semiconductor light emission devices provided with a stripe of the first multilayer and the second multilayer having different emission wavelengths.

RELATED APPLICATION DATA

This application is a division of U.S. patent application Ser. No.11/331,398, filed Jan. 12, 2006, the entirety of which is incorporatedherein by reference to the extent permitted by law. The presentinvention claims priority to Japanese Patent Application Nos.2005-018368 and No. 2005-018369 filed in the Japan Patent Office on Jan.26, 2005, the entirety both of which also are incorporated by referenceherein to the extent permitted by law.

BACKGROUND OF THE INVENTION

The present invention relates to a method of production of asemiconductor light emission device and a method of production of alight emission apparatus, more particularly relates to a method ofproduction of a semiconductor light emission device provided with aplurality of multilayers emitting lights having different wavelengthsand a light emission apparatus mounting the semiconductor light emissiondevice in a package.

In general, an apparatus for reading (reproducing) information recordedon a compact disc (CD), digital versatile disc (DVD), mini disc (MD), orother optical recording medium for optically recording information(hereinafter also referred to as an “optical disc”) or writing(recording) information on them (hereinafter also referred to as an“optical disc apparatus”) includes a built-in optical pickup apparatus.

In the above optical disc apparatuses or optical pickup apparatuses, ingeneral, when the types of the optical discs (optical disc systems) aredifferent, use is made of laser beams having different wavelengths. Forexample, a laser beam having a wavelength of the 780 nm band is used forthe reproduction etc. of a CD, while a laser beam having a wavelength ofthe 650 nm band is used for the reproduction etc. of a DVD.

With the wavelengths of the laser beams differing according to the typesof the optical discs as described above, for example, a compatibleoptical pickup apparatus enabling the reproduction of a CD in an opticaldisc apparatus for a DVD has been demanded.

A monolithic two-wavelength laser mounting a laser diode for a CD(emission wavelength: 780 nm) and a laser diode for a DVD (emissionwavelength: 650 nm) on a single chip is widely used for constructing acompatible optical pickup apparatus enabling the reproduction of a CDand DVD described above. Greater reduction of the size and reduction ofthe cost of the chip have been demanded (see for example Japanese PatentPublication (A) No. 2000-244060, Japanese Patent Publication (A) No.2001-77457, and Japanese Patent Publication (A) No. 2001-244546).

In the above monolithic two-wavelength laser, a first multilayermaterial emitting light having a first wavelength is formed by crystalgrowth on a flat substrate, then is etched away at periodic intervals toform stripes of the first multilayer. After this, a second multilayermaterial emitting light having a second wavelength is formed by crystalgrowth on the substrate with the relief shapes formed by the stripes ofthe first multilayer and unnecessary parts are etched away to formstripes of the second multilayer between the stripes of the firstmultilayer.

SUMMARY OF THE INVENTION

In the crystal growth of the second multilayer material described above,the quality, uniformity, etc. of the crystals grown between the stripes(in the valleys) of the first multilayer become extremely important forthe function for emitting the second light.

Ordinarily, when the area of such a valley portion becomes narrow, thequality, uniformity, etc. of the crystals are degraded. Therefore, whenconsidering the yield and the uniformity of characteristics of thelaser, a certain extent of area becomes necessary. It is thereforedifficult to further reduce the chip size (width) in actualcircumstances.

The inventors found that the above difficulty can be overcome bychanging the order of arrangement of the stripes of two types ofmultilayers. In this case, however, two types of semiconductor lightemission devices with reverse arrangements of the two types ofmultilayers constituting the light emission regions are formed. For thisreason, when mounting the two types of semiconductor light emissiondevices in a package, some means for making them substantially the samelight emission apparatuses becomes necessary.

It is therefore first desirable to provide a method of production of asemiconductor light emission device able to reduce the size of thedevice while maintaining the uniformity of characteristics and theyield. It is second desirable to provide a method of production of asemiconductor light emission device able to improve the uniformity ofcharacteristics and yield without changing the size of the device. It isthird desirable to provide a method of production of a light emissionapparatus able to produce substantially the same light emissionapparatuses when mounting two types of semiconductor light emissiondevices having reverse arrangements of the two light emission regionshaving different emission wavelengths in a package.

According to a first aspect of the present invention, there is provideda method of production of semiconductor light emission devices forforming stripes of two multilayers having different emission wavelengthson a substrate, including the steps of: depositing a first multilayerincluding an active layer on the substrate; selectively etching thefirst multilayer to form a plurality of adjoining pairs of stripes ofthe first multilayer; depositing a second multilayer including an activelayer on the substrate and the stripes of the first multilayer;selectively etching the second multilayer to form a plurality ofadjoining pairs of stripes of the second multilayer on the substratebetween the stripes of the first multilayer; and dividing the substratebetween adjoining pairs of stripes of the first multilayer and betweenadjoining pairs of stripes of the second multilayer to divide it intosemiconductor light emission devices provided with stripes of the firstmultilayers and the second multilayers having different emissionwavelengths.

According to a second aspect of the present invention, there is provideda method of production of semiconductor light emission devices forforming stripes of a plurality of multilayers having different emissionwavelengths in semiconductor light emission device regions of asubstrate and dividing the substrate between the semiconductor lightemission device regions to form a plurality of semiconductor lightemission devices, wherein the process of forming stripes of theplurality of multilayers includes repeating a depositing step ofdepositing a multilayer including an active layer on the substrate and aprocessing step of processing the multilayer to form stripes of themultilayer and reversing the arrangements of stripes of a plurality ofmultilayers having different emission wavelengths in adjoining pairs ofsemiconductor light emission device regions to form pairs of stripes ofthe multilayers having the same emission wavelength adjacent to eachother between the semiconductor light emission device regions.

According to a third aspect of the present invention, there is provideda method of production of light emission apparatuses including the stepsof: producing a first semiconductor light emission device having twolight emission regions having different emission wavelengths and asecond semiconductor light emission device having a reverse arrangementof two light emission regions to that of the first semiconductor lightemission device; mounting the first semiconductor light emission devicein a first package to produce a first light emission apparatus; andinverting the second semiconductor light emission device so that thesame arrangement of the two light emission regions as that in the firstlight emission apparatus is obtained and mounting it in a second packageto produce a second light emission apparatus.

According to the method of production of the semiconductor lightemission device of the present invention, the size of the device can bereduced while maintaining the uniformity of characteristics and yield.Alternatively, according to the method of production of thesemiconductor light emission device of the present invention, theuniformity of characteristics and yield can be improved without changingthe size of the device. According to the method of production of thelight emission apparatus of the present invention, when mounting twotypes of semiconductor light emission devices with reverse arrangementsof two light emission regions having different emission wavelengths inpackages, it is possible to produce light emission apparatuses with thesame arrangements of light emission regions and therefore possible toproduce substantially the same light emission apparatuses.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and features of the present invention willbecome clearer from the following description of the preferredembodiments given with reference to the attached drawings, wherein:

FIG. 1 is a sectional view of a semiconductor light emission deviceaccording to an embodiment of the present invention;

FIGS. 2A and 2B are sectional views of steps in the production of asemiconductor light emission device according to an embodiment of thepresent embodiment;

FIGS. 3A and 3B are sectional views of steps in the production of asemiconductor light emission device according to an embodiment of thepresent embodiment;

FIGS. 4A and 4B are sectional views of steps in the production of asemiconductor light emission device according to an embodiment of thepresent embodiment;

FIGS. 5A and 5B are sectional views of steps in the production of asemiconductor light emission device according to an embodiment of thepresent embodiment;

FIG. 6 is a view showing an arrangement of stripes of multilayers on asubstrate in the production of a semiconductor light emission deviceaccording to a comparative example;

FIG. 7 is a view showing the arrangement of stripes of multilayers on asubstrate in the production of a semiconductor light emission deviceaccording to an embodiment of the invention;

FIG. 8 is a perspective view of a light emission apparatus produced bymounting semiconductor light emission device in a package (firstpackage);

FIG. 9 is a sectional view of a semiconductor light emission devicemounted on a sub mount;

FIG. 10A is a plan view of the first package seen from the front side,and FIG. 10B is a plan view of the first package seen from the backside;

FIG. 11A is a plan view of a second package seen from the front side,and FIG. 11B is a plan view of the second package seen from the backside; and

FIG. 12 is a view of the configuration of an optical pickup apparatus.

DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be described indetail below while referring to the attached figures.

FIG. 1 is a sectional view of a semiconductor light emission deviceaccording to the present embodiment.

A semiconductor light emission device 1 according to the presentembodiment is a monolithic laser diode mounting a laser diode LD1 for aCD (emission wavelength: 780 nm) and a laser diode LD2 for a DVD(emission wavelength: 650 nm) on a single chip and is suitable forconstructing a compatible optical pickup apparatus enabling thereproduction of a CD and DVD.

The first laser diode LD1 includes an n-type substrate 30 made of forexample GaAs on which an an n-type buffer layer 31 made of for exampleGaAs, an n-type cladding layer 32 made of for example AlGaAs, an activelayer (multi quantum well structure) 33, a p-type cladding layer 34 madeof for example AlGaAs, and a p-type cap layer 35 made of for exampleGaAs are formed, whereby a first multilayer ST1 is formed.

Insulated regions 41 are formed from the surface of the p-type cap layer35 to a depth in the middle of the p-type cladding layer 34, whereby astripe forming a gain guided type current confined path structure isformed.

The second laser diode LD2 includes of an n-type substrate 30 on whichthe an n-type buffer layer 31 made of for example GaAs, an n-type bufferlayer 36 made of for example InGaP, an n-type cladding layer 37 made offor example AlGaInP, an active layer (multi quantum well structurehaving an emission wavelength of 650 nm) 38, a p-type cladding layer 39made of for example AlGaInP, and a p-type cap layer 40 made of forexample GaAs are formed, whereby a second multilayer ST2 is formed.

The regions other than the portion for forming a current injectionregion are removed from the surface of the p-type cap layer 40 to adepth in the middle of the p-type cladding layer 39 to form a currentinjection region having an upwardly projecting ridge shape RD to form astripe forming a gain guided type current confined path structure.Further, it is also possible to easily prepare an index guided type,self pulsation type, etc. by the control of the ridge depth, shape, etc.

Further, an insulation film 44 such as silicon oxide is formed coveringthe first laser diode LD1 and the second laser diode LD2. The insulationfilm 44 is formed with contact openings for exposing the p-type caplayers 35 and 40. p-side electrodes 42 are formed on the p-type caplayers 35 and 40, and an n-side electrode 43 is formed on a back surfaceof the n-type substrate 30. Note that the insulation film 44 is notalways necessary so long as the portions other than the stripes do notform ohmic contacts.

In the semiconductor light emission device 1 having the above structure,the distance between a light emission region P1 of the first laser diodeLD1 and a light emission region P2 of the second laser diode LD2 is setwithin for example a range of about 200 μm or less (about 100 μm). Fromthe light emission regions P1 and P2, for example a laser beam having awavelength of the 780 nm band and a laser beam having a wavelength ofthe 650 nm band are emitted parallel to the substrate and in almost thesame direction (almost parallel).

Next, an explanation will be given of the method of production of thesemiconductor light emission devices having the above configurationswith reference to FIG. 2 to FIG. 5.

First, as shown in FIG. 2A, for example metal organic vapor phaseepitaxial growth (MOVPE) or another epitaxial growth method is used todeposit a first multilayer material on a n-type substrate 30 made of forexample GaAs. As the first multilayer material, an n-type buffer layer31 made of for example GaAs, an n-type cladding layer 32 made of forexample AlGaAs, an active layer (multi quantum well structure having anemission wavelength of 780 nm) 33, a p-type cladding layer 34 made offor example AlGaAs, and a p-type cap layer 35 made of for example GaAsare stacked in that order.

Next, as shown in FIG. 2B, the first multilayer material is processed toform stripes of the first multilayer ST1. In the present embodiment, itis processed so that pairs of stripes of the first multilayer ST1 adjoineach other. Between each two pairs of stripes of the first multilayerST1, a distance large enough to form two stripes of the secondmultilayer ST2 is secured. The above processing is carried out byforming for example a resist film having the patterns of the stripes ofthe first multilayer ST1 and using nonselective etching of a sulfuricacid system and AlGaAs selective etching of a hydrofluoric acid systemor other wet etching (EC1) to remove the parts of the first multilayermaterial other than the regions protected by the resist film down to then-type cladding layer 32.

Next, as shown in FIG. 3A, for example metal organic vapor phaseepitaxial growth (MOVPE) or another epitaxial growth method is used todeposit a second multilayer material on the n-type buffer layer 31 andthe stripes of the first multilayer ST1. As the second multilayermaterial, an n-type buffer layer 36 made of for example InGaP, an n-typecladding layer 37 made of for example AlGaInP, an active layer (multiquantum well structure having an emission wavelength of 650 nm) 38, ap-type cladding layer 39 made of for example AlGaInP, and a p-type caplayer 40 made of for example GaAs are stacked in that order.

Next, as shown in FIG. 3B, the second multilayer material is processedto form pairs of stripes of the second multilayer ST2 between each twoadjoining pairs of stripes of the first multilayer ST1. In the presentembodiment, the pairs of stripes of the second multilayer ST2 areprocessed so as to be adjacent to each other. The above processing iscarried out by for example forming a resist film of the patterns of thestripes of the second multilayer ST2 and using cap etching of a sulfuricacid system, four-component selective etching of phosphoric acid andhydrochloric acid systems, separation etching of a hydrochloric acidsystem, or other wet etching (EC2) to remove the parts of the secondmultilayer material other than the regions protected by the resist filmdown to the n-type buffer layer 36.

Next, as shown in FIG. 4A, a current confined path structure is formedat each stripe of the second multilayer ST2. For example, in a stripe ofthe second multilayer ST2, regions other than the current injectionregion are removed from the surface of the p-type cap layer 40 to adepth in the middle of the p-type cladding layer 39 to form a ridgeshape RD having an upwardly projecting current injection region to forma gain guided type current confined path structure. The secondmultilayer ST2 is processed by forming a resist film open at regions tobe removed and then using the resist film as the mask for etching (EC3).Thereafter, the resist film is removed.

Next, as shown in FIG. 4B, a current confined path structure is formedin each stripe of the first multilayer ST1. For example, an impurity D1is introduced into the regions other than the current injection regionsof the stripes of the first multilayer ST1 by ion implantation or thelike to form insulated regions 41 from the surface of the p-type caplayer 35 down to a depth in the middle of the p-type cladding layer 34and thereby form gain guided type current confined path structures. Thisprocess is carried out by forming a resist film open at the ionimplantation regions, then implanting ions. Thereafter, the resist filmis removed.

Next, as shown in FIG. 5A, silicon oxide is deposited over the entiresurface by for example chemical vapor deposition (CVD) to form aninsulation film 44 and contact openings are formed for exposing thep-type cap layers 35 and 40. Subsequently, the p-type cap layers 35 and40 are formed with p-side electrodes 42 such as Ti/Pt/Au, while the backsurface side of the n-type substrate 30 is formed with an n-sideelectrode 43 such as AuGe/Ni/Au.

Next, as shown in FIG. 5B, the substrate is cleaved to divide it intosemiconductor light emission devices 1. By cleaving the n-type substrate30 between adjoining pairs of stripes of the first multilayer ST1 andadjoining pairs of stripes of the second multilayer ST2, semiconductorlight emission devices 1 provided with a stripe of a first multilayerST1 and a second multilayer ST2 are formed.

Next, an explanation will be given of the effects of the method ofproduction of the semiconductor light emission device with reference toa comparative example.

FIG. 6 is a view showing an arrangement of stripes of multilayers on asubstrate in the production of conventional semiconductor light emissiondevices described in the Japanese Patent Publication (A) No.2000-244060, Japanese Patent Publication (A) No. 2001-77457, andJapanese Patent Publication (A) No. 2001-244546. FIG. 7 is a viewshowing the arrangement of stripes of multilayers on a substrate in theproduction of semiconductor light emission devices according to theembodiment of the present invention.

As shown in FIG. 6, in the past, stripes of the first multilayer ST1 andstripes of the second multilayer ST2 are alternately formed one by one.For this reason, for example, when a chip width of a semiconductor lightemission device is W, if assuming that the stripe widths are uniform,the distance between stripes of the first multilayer ST1 in which thesecond multilayer material is grown becomes W/2.

Contrary to this, in the present embodiment, as shown in FIG. 7, pairsof stripes of first multilayer ST1 are formed so as to adjoin eachother, while adjoining pairs of stripes of the second multilayer ST2 areformed between each two adjoining pairs of stripes of the firstmultilayer ST1. For this reason, for example, when the chip width of asemiconductor light emission device is W, if assuming that the stripewidths are uniform, the distance between stripes of the firstmultilayers ST1 in which the second multilayer material is stackedbecomes W, and an area two times the conventional area can be secured.

As described above, by changing the order of arrangement of the stripesof the first multilayer ST1 and the stripes of the second multilayer ST2from the conventional order, the area between stripes of the firstmultilayer ST1 can be made substantially twice the previous size, so itbecomes easy to more stably secure the quality, uniformity, etc. ofcrystals of the second multilayer material. Namely, it becomes possibleto reduce the chip size (width) of individual semiconductor lightemission devices 1 without degrading the quality, uniformity, etc. ofcrystals, and the yield from one wafer (n-type substrate 30) can beeasily improved. Accordingly, further reduction of size and reduction ofcost become possible while keeping the yield and the uniformity ofcharacteristics of the lasers.

Alternatively, the areas for the stripes of the second multilayermaterial, that is, the areas between stripes of the first multilayerST1, can be made larger without changing the chip sizes (widths) of thesemiconductor light emission devices 1. For this reason, when the chipsizes of the semiconductor light emission devices 1 are the same as theconventional size, it becomes possible to further improve the quality,uniformity, etc. of crystals of the second multilayer material formed bycrystal growth between stripes of the first multilayers ST1, and itbecomes possible to more stably produce lasers having high yield anduniformity.

Further, in the present embodiment, the chip sizes can be changed byjust changing the order of arrangement of stripes of multilayers on thewafer (n-type substrate 30), therefore the effects are also exhibitedthat design is extremely easy and almost no development costs areincurred.

As shown in FIG. 7, in the method of production of semiconductor lightemission devices described above, two types of semiconductor lightemission devices having reverse orders of arrangement of stripes ofmultilayers are produced. Usually, dielectric layers are formed on theend faces of both sides of each semiconductor light emission device 1.When these two dielectric films are the same, the semiconductor lightemission devices 1 may be regarded as of one type. However, when thedielectric films are different, the semiconductor light emission devicesbecome two types having reverse arrangements of light emission regions.

In the method of production of light emission apparatuses according tothe present embodiment, when two types of semiconductor light emissiondevices having reverse arrangements of light emission regions areproduced, the production of same light emission apparatuses is enabled.

FIG. 8 is a perspective view of a light emission apparatus 1 produced bymounting the semiconductor light emission device 1 in a package l0(first package). The first package 10 shown in FIG. 8 is a so-called CANpackage. In FIG. 8, the side indicated by an arrow Y1 in the figure isthe front side (light output side) of the first package 10, and the sideindicated by an arrow Y2 becomes the back side.

A disk-shaped base 11 has a heat sink 12 fixed to it. The heat sink 12is formed by for example a metal material having a good heatconductivity and low resistance. On the heat sink 12, a sub mount 13 ismounted. On the sub mount 13, a PIN diode 2 forming a monitor usephotosensor and a semiconductor light emission device 1 provided withfirst and second laser diodes LD1 and LD2 are mounted.

The PIN diode 2 senses the laser beams emitted to the rear sides of thefirst and second laser diodes LD1 and LD2. It is configured to measurethe intensities of the laser beams and thereby control the drivecurrents of the first and second laser diodes LD1 and LD2 so as to giveconstant intensities of laser beams for automatic power control (APC).

As external terminals, provision is made of a PIN diode use terminal 14passing through the base 11, an LD1 use terminal 15, and an LD2 useterminal 16. Further, the back surface of the first package is providedwith a common terminal 17 connected to the heat sink 12.

One electrode of the PIN diode 2 and the PIN diode use terminal 14 areconnected by a lead 21. The other electrode of the PIN diode 2 and theheat sink 12 are connected by a lead 22. Due to this, the otherelectrode of the PIN diode 2 and the common terminal 17 are connected.

The electrode of the first laser diode LD1 of the semiconductor lightemission device 1 and the LD1 use terminal 15 are connected by a lead23, while the electrode of the second laser diode LD2 and the LD2 useterminal 16 are connected by a lead 24. The common electrode (n sideelectrode) of the semiconductor light emission device 1 and the heatsink 12 are connected by a lead 25. Due to this, the common electrode ofthe semiconductor light emission device 1 and the common terminal 17 areelectrically connected.

Between the common terminal 17, the PIN diode use terminal 14, the LD1use terminal 15, and the LD2 use terminal 16, a drive voltage able todrive the semiconductor light emission device 1 and the PIN diode 2 issupplied.

FIG. 9 is a cross-sectional view of the semiconductor light emissiondevice 1 mounted on the sub mount 13.

The semiconductor light emission device 1 is connected and fixed fromthe p-side electrode 42 side to an electrode 13 a formed on the submount 13 by solder etc. The lead 23 is connected to the electrode 13 aconnected to the p-side electrode 42 of the first laser diode LD1. Thelead 24 is connected to the electrode 13 a connected to the p-sideelectrode 42 of the second laser diode LD2. The lead 25 is connected tothe n-side electrode 43 common to the laser diodes LD1 and LD2.

In the semiconductor light emission device 1 mounted on the sub mount 13described above, a first laser beam is emitted from a light emissionpoint (light emission region) P1 in the first active layer 33 of thefirst laser diode LD1. Further, a second laser beam is emitted from alight emission point (light emission region) P2 in the second activelayer 38 of the second laser diode LD2.

FIG. 10A is a plan view of the light emission apparatus 10 shown in FIG.8 seen from the arrow Y1 side (light output side, front side), whileFIG. 10B is a plan view of the light emission apparatus 10 shown in FIG.8 seen from the arrow Y2 side (back side). Note that, in FIGS. 10A and10B, the PIN diode use terminal 14 is omitted.

As shown in FIG. 10A, when viewed from the light output side, a lightemission apparatus 10 is obtained in which the light emission point P1of the first laser diode LD1 is arranged on the right side and the lightemission point P2 of the second laser diode LD2 is arranged on the leftside.

In the method of production of the semiconductor light emission devicesdescribed above, two types of semiconductor light emission deviceshaving reverse arrangements of light emission points are produced. Asshown in FIGS. 10A and 10B, where one semiconductor light emissiondevice is mounted in a first package, the other semiconductor lightemission device is mounted as shown in FIG. 11.

FIG. 11A is a plan view of the light emission apparatus produced bymounting the other semiconductor light emission device in a secondpackage 11 seen from the light output side (front side), while FIG. 11Bis a plan view of the light emission apparatus seen from the back side.Note that, in FIGS. 11A and 11B, the PIN diode terminal 14 is omitted.

As shown in FIGS. 11A and 11B, the second package 11 for mounting theother semiconductor light emission device has the same terminalarrangement, but is inverted in internal structure in comparison withthe first package.

Namely, the internal structure of the second package 11 is configured asthe first package rotated 180° about the light output axis (directionvertical to the paper surface in the figure). In this way, the heat sink12 and the sub mount 13 are arranged and the semiconductor lightemission device 1 is mounted on the sub mount 13 inverted from the firstpackage. In this way, the orientation of the semiconductor lightemission device 1 mounted in the second package 11 is inverted incomparison with the semiconductor light emission device 1 in the firstpackage. As a result, in a state mounted in the second package 11, thearrangement of the light emission points P1 and P2 of the semiconductorlight emission device 1 becomes the same as the arrangement of lightemission points P1 and P2 of the semiconductor light emission device 1mounted in the first package.

Further, the first package and the second package become the same in thearrangements of the external terminals, that is, the PIN diode useterminal 14 (not shown), LD1 use terminal 15, LD2 use terminal 16, andcommon terminal 17, when seen from the back surface side of the package.

In this way, the arrangement of light emission points when seen from thelight output surface side and the arrangement of external terminals whenseen from the back surface side become the same, therefore one type oflight emission apparatus is prepared as the light emission apparatus 10formed by packaging the semiconductor light emission device 1.

FIG. 12 is a view of the configuration when a light emission apparatus10 packaging a semiconductor light emission device 1 is used in anoptical system pickup apparatus in an optical disc system havingdifferent wavelengths for CDs and DVDs.

An optical pickup apparatus 100 has optical systems constitutedindividually, that is discretely, for example a light emission apparatus10 having a first laser diode LD1 emitting a laser beam having awavelength of for example the 780 nm band and a second laser diode LD2emitting a laser beam having a wavelength of the 650 nm band, a gratingG used for the 780 nm band and passing the laser beam of the 650 nm bandtherethrough, a beam splitter BS, a collimator C, a mirror M, a CD useopening limiting aperture R, an object lens OL, a multi lens ML, and aphotodiode PD arranged at predetermined positions. In the photodiode PD,for example a first photodiode receiving the light of the 780 nm bandand a second photodiode receiving the light of the 650 nm band arearranged in parallel adjacent to each other.

In the optical pickup apparatus 100 having the above configuration, thefirst laser beam L1 from the first laser diode LD1 passes through thegrating G, is partially reflected by the beam splitter BS, passesthrough or is reflected at the collimator C, the mirror M, and the CDuse opening restriction aperture R, and is focused onto the optical discD by the object lens OL.

The light reflected from the optical disc D passes through the multilens ML via the object lens OL, the CD use opening limiting aperture R,the mirror M, the collimator C, and the beam splitter BS and isprojected onto the photodiode PD (first photodiode). By the change ofthis reflected light, the information recorded on the recording surfaceof the optical disc D such as a CD is read out.

On the other hand, the second laser beam L2 from the second laser diodeLD2 follows the same route as that described above to be focused ontothe optical disc D. The reflected light thereof is projected onto thephotodiode PD (second photodiode). The information recorded on therecording surface of the optical disc D such as a DVD is read out by thechange of this reflected light.

As explained above, by the method of production of light emissionapparatuses according to the present embodiment, even in the case whentwo types of semiconductor light emission devices having reversearrangements of light emission points are prepared, light emissionapparatuses having the same arrangement of light emission points areprepared as packaged light emission apparatuses 10, therefore it is notnecessary to change the arrangement of optical systems of the opticalpickup apparatuses 100.

Further, by making the arrangements of the external terminals of the twolight emission apparatuses 10 packaging two types of semiconductor lightemission devices 1 the same, it becomes unnecessary to change thearrangement of power supply, so these can be handled as substantiallythe same type of light emission apparatus.

In this way, they can be regarded as the same type of light emissionapparatus after packaging. Therefore, this can contribute to the yieldof the method of production of semiconductor light emission devices.

The present invention is not limited to the explanation of theembodiment described above. In the present embodiment, an exampleconcerning the most general monolithic two-wavelength laser wasexplained, but the present invention can also be applied to the case ofa monolithic laser of three or more wavelengths. In the case of three ormore wavelengths, it may be formed by reversing arrangements of theplurality of stripes of the multilayers having different emissionwavelengths between adjacent semiconductor light emission device regionsand forming two stripes of multilayers having the same emissionwavelength adjacent across semiconductor light emission device regions.Namely, when defining stripes of multilayers having different emissionwavelengths as A, B, and C, the stripes of the multilayers are formed inan order of arrangement such as A, B, C-C, B, A-A, B, C . . . . Due tothis, stripes (for example, A, C) of the multilayer material for which alarge area must be secured continue while sandwiching semiconductorlight emission device regions. Then, by cleaving the substrate at theboundary of the semiconductor light emission device regions,semiconductor light emission devices individually providing stripes ofmultilayers having emission wavelengths different from each other areproduced.

For example, in the present embodiment, an explanation was given bytaking as an example a CAN package as the package, but the presentinvention can also be applied to mounting onto a package other than aCAN package. In this case as well, by mounting while inverting thesemiconductor light emission device 1 front to back, arrangements oflight emission points of two types of semiconductor light emissiondevices 1 can be made the same when seen from the light output side ofthe light emission apparatus.

Further, the semiconductor light emission device used in the presentinvention is not limited to laser diodes. Light emission diodes (LED)can also be employed. Further, the emission wavelengths of the first andsecond laser diodes are not limited to the 780 nm band and 650 nm band.A wavelength employed in another optical disc system can also beemployed.

Further, it is also possible to form the first laser diode LD1 as aridge type and form the second laser diode LD2 as an ion implantationtype. It is also possible to give the ridge type or ion implantationtype current confined path structure to both of the first laser diodeLD1 and second laser diode LD2.

Other than this, various changes are possible within a range not out ofthe gist of the present invention.

It should be understood by those skilled in the art that variousmodifications, combinations, sub-combinations and alterations may occurdepending on design requirements and other factors insofar as they arewithin the scope of the appended claims or the equivalents thereof.

1. A method of producing at least two light emission apparatusescomprising the steps of: producing a first semiconductor light emissiondevice having two light emission regions P1 and P2 arranged next to eachother in this order; producing a second semiconductor light emissiondevice having two light emission regions P2 and P1 arranged next to eachother in this order; mounting said first semiconductor light emissiondevice in a first package to produce a first light emission apparatus;and inverting said second semiconductor light emission device and thenmounting it in a second package to produce a second light emissionapparatus, wherein, each of said light emission regions P1 and P2 isconfigured to emit light of a different wavelength.
 2. The method ofclaim 1, further comprising the step of: providing a plurality ofexternal terminals at the same positions on said first package and saidsecond package, the external terminals effective to supply current tothe first and second semiconductor light emission devices.
 3. The methodof claim 1, further comprising the steps of: mounting said firstsemiconductor light emission device on a first internal mount member inthe first package, and mounting said second semiconductor light emissiondevice on a second internal mount member in the second package, wherein,said internal mount member of said second package is inverted to saidinternal mount member of said first package.
 4. The method of claim 1,wherein said step of producing said first semiconductor light emissiondevice and said second semiconductor light emission device include thesteps of: depositing a first multilayer including an active layer onsaid a substrate; selectively etching said first multilayer structure toform a plurality of adjoining pairs of stripes of said first multilayerstructure; depositing a second multilayer structure including an activelayer on said substrate and said stripes of said first multilayerstructure; selectively etching said second multilayer structure to forma plurality of adjoining pairs of stripes of said second multilayerstructure on said substrate between said stripes of said firstmultilayer structure; and dividing said substrate between adjoiningpairs of stripes of said first multilayer structure and betweenadjoining pairs of stripes of said second multilayer structure effectiveto divide said substrate into said first semiconductor light emissionapparatus and said second semiconductor light emission apparatus.